Pneumatic conveying system and method



Oct. 30, 1951 J. J. ISRAEL 2,572,862

PNEUMATIC CONVEYING SYSTEM AND METHOD JOHN J. ISRAEL A T TORNEYS.

Oct. 30, 1951 J. J. ISRAEL PNEUNATIC CONVEYING SYSTEM AND METHOD 8 Sheets-Sheet 2 Filed Feb. 15, 1947 FIGA-b.

#2 N m m 5 FIG.4C1.

FIG. 4b.

Oct. 30, 1951 J. J. ISRAEL PNEUMATIC CONVEYING SYSTEM AND METHOD 8 Sheets-Sheet 3 Filed Feb. 13, 1947 COLLECTOR *es n n INVENTR John J Israel, deceased,

Oct. 30, 1951 J. J. ISRAEL PNEUMATIC CONVEYING SYSTEM AND METHOD 8 Sheets-Sheet 4 Filed Feb. 13, 1947 FIG. 4d.

i .x un 22 232 CLEAR 221 228 I I l l I.

2.44- PATENT INVENTOR A John J fsrae, deceased, ylay. f5

J. J. ISRAEL PNEUMATIC CONVEYING SYSTEM AND METHOD Oct. 30, 1951 8 Sheets-Sheet 5 Filed Feb. 13, 1947 FIGA-G.

zsz COLLECTOR *6/ INVENTOR John .f Israel, deceased,

Oct 30, 1951 J. J. ISRAEL PNEUMATIC CONVEYING SYSTEM AND METHOD 8 Sheets-Sheet 6 Filed Feb. 13, 1947 mm, m mw m w vw K ww uw m uw QS ma@ W mv .f mm; w I W E @17% .O `W v .l j J. Nm, .,x `x. www mv QM, l www Wm, l R. ow Nv mm S W QW vw NQ@ dw MW Q\ wm.

En ww @QQ R R mom. w m@ m6 wm mm mw \w\ wm mw vw wm mm uw AT TORNEYS.

Oct. 30, 1951 .1. J, ISRAEL PNEUMATIC CONVEYING SYSTEM AND .METHOD 8 Sheets-Sheet 7 Filed Feb. 13, 1947 ATTORNEYS.

Oct. 30, 1951 .1. J. ISRAEL 2,572,862

PNEUMATIC CONVEYING SYSTEM AND METHOD F'led Feb. 13, 1947 8 Sheets-Sheet 8 INVENTOR.

JOHN J. ISRAEL m] v )L7/WML ATTORNEYS.

Patented Oct. 30, 1951 2,572,862 l PNEUMATIC CONVEYING SYSTEM ANI? METHOD John J. Israel, Merrick, N. Y.; Ray S. Israel, ad-

ministratrix of said .John J. Israel, deceased, assixnor to Ray S. Israel, Merrick, Long` Island,

Application February 13, 1947, Serial No. 728,222

28 Claims. l This invention relates to the storing and handling of bulk products, and more in particular to a system for storing, conveying, measuring and processing flour or the like.

is weighed out and conveyed to any selected dough-mixing station and the process is carried on rapidly and efliciently. One or two operators may control the entire system and if there are An object of this invention is to provide a fullyf two operators, the use of the system by one auautomatic system for handling flour or the like tomatically locks out the control switches for in a storage or processing plant such, for exthe other. The operation of the conveyor sysample, as in a bakery. A further object is to tem is completely automatic after being once provide a system for conveying, weighing and started, and it is self-cleaning so that it is left otherwise processing ilour or the like in an etho in condition for immediate re-use. cient manner which avoids certain of the dis- The present invention has the outstanding advantages of the prior systems. A further obfurther advantage that it facilitates the hanject is to provide a system of the above character dling of the problem of insect infestation. In wherein flour or the like may be stored and bakeries, flour mills and storage warehouses for handled in such a manner as to insure that it will l?) cereals and cereal products the problem of inremain unadulterated; thus, for example, so as sect infestation has been a very serious one. In to avoid the problems of insect infestation.. A fact, this problem is present throughout the further object is to provide such a system wherein cereal industry, that is, from the producer oi' Wastage of the product is at a minimum. I'hese the grain to the ultimate consumer; the value of and other objects will be in part obvious and in the various grains and cereal products thus lost part pointed out below. amounts to millions of dollars every year. This In the drawings: problem has arisen mainly due to two factors Figure 'l is a schematic showing of a system which are, the ever-present sources of insect life. for handling and processing flour in a large bak-i and the ever-present breeding places where inery wherein there is provision for unloading the sect life is permitted to propagate freely under flour into storage bins and also provision for ideal conditions. That is, cereals are invariably sifting, weighing and conveying the flour to varinfested with one or more types of insect life ious dough-mixing stations; and the various plants, including the mills, be-

Figures 2 and 3 are enlarged sectional views come infested as the cereal and cereal products of structural elements appearing in Figure 1; 30 enter the mills. With the mills thus infested, it

Figures 4a, 4b, 4c, 4d, 4e are a simplified scheis difdcult to prevent the infestation of the varimatic wiring diagram of the system of Figure 1, ous outgoing products such as flour. These with certain of the duplicate equipment omitproducts are stored in warehouses and in procted; and, essing plants where they are to be used and dur- Figures 5, 6 and 7 are views similar to Figure 1 35 ing storage such infestation as is present propashowing other embodiments of the invention. gates very rapidly.

The illustrative embodiment of the invention With the handling equipment for flour and like is a system for handling the flour which is used products which has been available in the past in a large bakery. The flour may be received by there are numerous pockets and recesses in which the system from bags or in bulk from railway 40 the products accumulate with the result that incars or trucks. Two orv more types of flour may festation is given an ideal oportunity to propbel used and these arestored separately or in agate, For example, there are dead spaces blended miXtllleS 111 bins, but yet a single conin screw and bucket conveyors where the prodveyor system is used for the diierent types 0f uct accumulates and remains stationary during flour. The 260111 1S received and Stored On a 45 use of the equipment, and these dead Spaces lower floor of the building and automatic doughare generally centers of insect infestation Furmixing equipment is located on an upper floor of thm-more, during handling, these products esthe building- Tlle Olll may be blended, Siflied, cape in the form of dust and float through the Stored and weighed 0n the lower f100`1" and air and settle upon all horizontal surfaces in the weighed batches of ilour are conveyed as needed plant; when an appreciable layer of dust thus to the dough-mixing equipment. Illustratively, accumulates, the dust provides an ideal place for there are six dough-mixing stations on the upinsect propagation. In many plants it is a rou- Der 11001' representing SiX Sets 0f dough-mixing tine practice to clean and fumigate at regular equipment of known construction. With this intervals, but thisrequires that the plant be system any quantity of the selected type of flour closed for a period of time and the use ot fumi- 3 gants is objectionable. During this periodic cleaning the "dead spaces are-cleaned out, but normally the products which are thus removed are infested so that they must be discarded and this represents a substantial loss.

In addition to the infestation problem, often there is a substantial loss due to dust which escapes during Yhandling because this too becomes contaminated and must be discarded. Furthermore', in plants which use two or more different products, such as the different types of our which are used in a bakery, the products which collect in the "dead spaces should be cleaned out when a different type of product is to be handled in the conveying system; otherwise, the flour handled subsequently becomes adulterated by the prior accumulations.

In accordance with the present invention the product is handled in such a manner as to avoid the escape of dust and the entire system is free of dead spaces. Furthermore, it has been found that insect infestation does not propagate and, in fact, it may be destroyed during the conveying operations. The product is conveyed in a stleam of air through conduits which have streamlined interiors so that there are no dead spaces, and the product is separated from the air in such a manner as to avoid the discharging 'if dust with the air. Thus, the entire plant is free of product accumulations, and such infestation as does enter the plant can be destroyed and there is still no great infestation problem.

Avoiding the escape of dust into the air is also very important from the standpoint that it eliminates the explosion hazard. That is, with the prior hour-handling systems there was sufficient our dust in the air throughout the plant to make the danger of a dust explosion a real problem. With flour-conveying systems built in accordance with the present invention the our is thoroughly removed from the air streams at the collectors and dust does not escape into the plant; thus, the atmosphere in the plant is kept free of iiour dust.

In the illustrative embodiment of the invention a flour-handling system for a bakery is provided wherein each of two or more kinds of flour is unloaded from bags, barrels, freight cars or trucks and is stored in its bin. Before storage the our is sifted and if desirable it can be conditioned, for example, by cooling or heating it, or by tempering it by adding moisture, or by removing moisture. That is, the air used for conveying the flour is given the necessary temperature and humidity to properly condition or temper the our and the intimate contact between each particle of our and the air insures that the conditioning will be thorough. Furthermore, all of the moisture which is added to the our is thoroughly absorbed and an "equilibrium condition is reached wherein there is no free moisture in the air at the time the stream reaches the collectors. Likewise, when moisture is removed from the iiour the stream reaches the collector only after a similar "equilibrium condition hasA been reached. Therefore, whether moisture is removed or added, there are no globules of water knocked out of the stream due to cyclonic laction in the collectors. With the present system, the flour may have additional` materials added to it, such, for example, as fortifying materia1s; and these are thoroughly mixed with the our. The system also provides for the withdrawing of flour selectively from the various bins and for weighing the our into batches as desired.

These batches are conveyed selectively to the six diiferent dough-mixing stations on an upper floor of the bakery. Illustratively, adjacent the point where iiour is received by the system there is a flour-receiving control station at which is located the control equipment for delivering the flour to the bins and for performing the various desired functions on the system. Adjacent the dough-mixing stations are two batch-selecting control stations each of which controls the delivery of our to three of the six dough-mixing stations. At these control stations the weight and type of iiour as Well as the destination (i. e., the desired dough-mixing station) may be selected for each batch of flour, and the entire weighing and conveying operation is controlled. After this selection of the type and weight of our and the destination of the batch, the operation will be carried on automatically as desired.

As indicated above, the flour is conveyed through pipes or conduits to the various destinations by fast moving streams of air. There is a separating unit or collector at each destination, that is, at the sifter and at each bin and dough-mixing station. As a our-laden stream of air is directed to one of these collectors the iiour is separated from the air and is discharged at the bottom of the collector; the stream of air is passed either to exhaust or back to the inlet for the conduit. These collectors may have two stages, a primary stage which removes the major portion of the flour and a secondary stage which removes the remainder of the our. With these collectors, the our-laden stream of air is delivered to the first stage where the greater portion of the iiour is extracted; the stream then flows at a rapid rate to the second stage where the remainder of the iiour is removed from the air. In passing from the primary stage to the secondary stage, the stream of air flows at a sufficiently rapid rate to hold the our in suspension. Otherwise small amounts of the flour drop out and may accumulate, thus forming a. zone for the propagation of insect life.

As indicated above, a reduction in the insect infestation problem is brought about by the avoidance of our accumulations where insect life may propagate. In addition to this factor, it has been found that at least certain types of insect life are destroyed in the conveying system. It should be noted that the rate of flow is very rapid in the conduits and in the collectors, and the infestation destruction may result from this high speed or from life-destroying impacts against the conduit and collector walls.

Referring particularly to Figure 1 of the drawings, the apparatus for receiving our is represented at the left by a iiourreceiving hopper 2 and as flour is received it is dumped into this hopper. At the bottom of this hopper is a rotary feed valve 4, the rotor of which is turned at a constant speed so as to carry measured quantities of the iiour from the hopper around to the bottom of the valve where it is deposited into an aerator 6 connected into conduit 8.

As best shown in Figure 2, aerator 6 has four transverse vanes positioned directly beneath valve 4 so that the i'lour dropping from the valve cascades to the right down the vanes. 'I'here are three narrow vanes 5 and a bottom wide vane l, and a steady stream of air iows from left to right through the aerator so that the flourl is picked up and entrained in the stream of air. The air enters conduit 8 at the left through an air dlter 8 and it passes with the flour entrained therein to a two-stage co1- lector I0 of the cyclone separator type. Collector I 0 has an outer primary stage collector II and a concentrlcally positioned inner secondary stage collector I2.

Flour from the primary stage passes through a hopper I4 having a vibrator I3 to a valve I6 which delivers the flour through a flexible conduit coupling I1 to a sifter I8. Flour -from the secondary stage passes through a similar hopper, a valve I9 and a ilexible conduit coupling 28 to sifter I8. The flour-free air is drawn from the top of the collector through a conduit 22, having at the left an adjustable damper or blast gate 24, by a fan 26 which exhausts the air to atmosphere through a conduit 28.

Conduit 8 has a smooth, streamlined interior so that there are no crevices or pockets where flour may collect. Fan 26 is located at the exhaust with the result that the system operates as a suction system: thus, ilour is picked up by the aerator and is carried to the collector where it is separated from the air, and this conveying operation is carried on in an eilcient and dependable manner. The rotor of valve 4 is turned at a controlled constant speed with the result that ilour is supplied to the stream of air at the maximum rate consistent with elllcient operation.

Within the sifter foreign materials are separated from the flour and the clean flour passes through a flexible conduit 30 and a rotary valve 32 to an aerator 33 where it is entrained in a stream of air carried by a conduit 34, the ar rangement being similar to the arrangement for entraining flour from hopper 2 into the stream of air in conduit 8. However. the air passes through conduit 34 due to pressure -rather than suction, there being at the left a fan 36 which draws air in through an air illter 35 and delivers air to the conduit at a pressure which is controlled by a blast gate 31.

Conduit 34 extends to the right where a motorized selector valve 38 directs the flour-laden stream of air to the left to a bin 40 or to the right to a bin 42. the destination of the iiour depending upon the position of the valve vane. Bins 40 and 42 are cylindrical and the ilourladen stream of air enters tangentially so that the major portion of the flour is separated from the air in the selected bin by cyclonic action. The air is discharged from the top centers oi the bins through a conduit 43 which extends to the left to a cyclone separator type of collector 44, where the remainder of the ilour is separated from the air and the flour-free air is discharged to atmosphere through a conduit 45. The ilour is discharged through the hopper bottom ofcollector 44 by a valve 4I, and aflexible conduit coupling to the sifter, the arrangement being similar to -that for discharging flour from collector I0.

Under some circumstances the stream of flourladen air from conduit 34 may be passed directly to a collector 44 so that the entire separating action is in the collector and the flour from the collector is discharged into the selected bin 40 or 42. However, by discharging the stream of hour-laden air into the top of the bin, there is a suilicient separating action to cause the major portion of the ilour to be dropped out into the bin. Therefore, the air which enters separator 44 contains only a relatively small percentage of the total amount of flour which the stream of air in conduit 34 carries and separator 44 performs its separating operation more emciently with less restriction in the flow of air.

The bottom of bin 40 is provided with a rotary valve 46 which discharges through a ilexible coupling 41 into a scale hopper 48. Similarly, at the bottom of bin 42 is a rotary valve 58 which discharges through a flexible coupling 5I into the scale hopper. Thus, by selectively rotating the rotors of valves 46 and 50, ilour from either of the two bins can be delivered to the scale hopper and a weighed quantity or batch cf ilour from eitherv of the bins can thus 'Je obtained. Beneath each oi valves 45 and 50 is a double-vane cut-off valve 48 which is closed to stop the delivery of flour to the scale hopper immediately upon the quantity of ilour inthe scale hopper reaching the desired weight. Control means is provided to select the type and weight o1' each batch of flour and the weighing operation is car ried on automatically.

At the bottom of the scale hopper is a rotary valve 52 which delivers the ilour at the end of the weighing operation through a flexible coupling 54 to an aerator 56 which is similar to aerator 6. Aerator 56 ispositioned in a conduit 58 through which a stream of air is directed from the left by a fan 60. Fan 60 draws in clean air through a conduit 53 and a filter 55 and the pressure in conduit 58 is controlled by a blast gate 51.

The flour-laden stream of air passes to the right through conduit 58 and thence up to the dough-mixing stations on an upper tloor of the building. On this upper door conduit 58 passes adjacent the six dough-mixing stations at each of which is a collector, numbered 6I to 68, inclusive, which are similar to collector I0. Each of these collectors is adapted to receive the ilourladen stream of air from conduit 58 and to separate the ilour therefrom. The flour is delivered from the hopper bottom of each of the collectors to its dough-mixing machine by opening a double-vane ilap valve 1I with the arrangement being such that the left-hand vane of the valve seals ofi the bottom of the primary stage of its collector and the right-hand vane seals oi! the bottom of the secondary stage. The flour-free air is discharged to atmosphere through a conduit 61 to which all of the collectors are directly connected. The left-hand collector 66 is directly connected to conduit 58 and each of the other collectors may be connected to this conduit by its two-position flap valve 68, the structure of which is shown best in Figure 3. The vanes of these valves are normally in the broken-line position of Figure 3 flush with the side of conduit 58, and when the vane of a particular valve is moved to the full line position of Figure 3 the flourladen stream of air is diverted from conduit 58 to the adjacent collector. Thus, during operation, if the ilour is to be delivered to one of the collectors 6I to 65, inclusive, the appropriate valve is swung to the broken line position, but if the our is to be delivered to collector 65 the valves all remain in their normal positions. Conduit 58 terminates in collector 66 but the flour-laden stream of air may be diverted from the conduit before it reaches this collector. In this way the ilour is never discharged through conduit 61 because the stream is received by collector 66 if it is not diverted-by one of valves 68.

As indicated above, the present system provides for the weighing out o! pre-determined quantities or batches of our from either bin 40 or bin 42, and each weighed quantity is delivered to any selected one of the dough-mixing stations. The electrical circuit for this flour'- weighing and conveying mechanism is represented schematically and in somewhat simplied form in Figure 4a. Illustratively, there are two control stations positioned adjacent the doughmixing stations; station #I controls the delivery of flour to collectors 6|, 62 and 63, and station #2 controls the delivery of iiour to collectors 64. 65 and 66.

Referring to lFigure 4b, the scale hopper 48 is represented in schematic form at the top, and these two control stations are represented beneath the hopper.

At each of these control stations is a scale control head by means of which the scale may be set for any selected weight, and there is an indication at the scale head of the weight setting as well as a continuous indication of the quantity of material which is in the scale hopper. During the weighing operation the movement of the scale hopper operates control switches with the result that the rate of feed to the hopper is reduced when the amount of flour in the hopper approaches the desired weight, and then the feed is stopped when the desired weight has been reached. At each of the control stations there are switches which are operated to control the selection of the type of our and the weighing and conveying operations so that each quantity or batch of flour is delivered to the selected collector at a dough-mixing station. At each of the dough-mixing stations is a set of mechanism and these sets of mechanism are identical at the various stations except that there is no valve 68 and its mechanism at collector 66. In Figures 4c and 4e the control circuits and associated mechanism for stations 6|, 65 and 66 are represented and the corresponding mechanism for the other three stations is omitted. The various duplicate elements of the different stations are given the same numerals except that suffixes are added identifying the particular sta tions; that is, the elements for collector 6| have no sulhxes, but the suiiixes and 6 are added to the respective numerals identifying the identical elements for collectors 65 and 66.

The mechanism for performing the various weighing and conveying operations for the system are represented in the lower portion of the figure and these are boxed in broken lines and are referred to herein by descriptive names for ready identification. In the lower portion of the figure, the mechanism for feeding fiour from the clear flour bin 42 is represented at '80, and at the left of this the corresponding mechanism for feeding patent our from bin 40 is represented at 82. There are also the following: the patent iiour selecting relay mechanism 84; the clear flour selecting relay mechanism 86; a bin protecting relay assembly 8B which prevents the delivery of flour from either of bins 40 or 42 after delivery has been started from the other bin; a patent flour control relay 92 which controls the feed motor which rotates valve 46 to feed flour from bin 40; asimilar clear flour control relay 90 which controls the feed motor which rotates valve 52 to feed flour from bin 42, at the right, an air feed relay 94 which controls a valve motor relay 96, which, in turn, controls a motor 91. Motor 91 rotates valve 52 thus to deliver flour from the scale hopper 48 to the stream of air in conduit 58. The air feed relay 94 also controls the energization of a hopper discharge relay 98 thus to operate the scale hopper-discharge valve 52 so as to cause the' ilour to flow from the hopper and also to energize a vibrator |00 positioned on the side of the scale hopper which vibrates the hopper wall when flour is being delivered from the hopper. This vibrator insures that the our will fiowAin an even stream through valve 52 so that it is delivered to the air stream in an efficient manner.

Directly above relay 94 is a blowout relay |02 which holds the air feed relay 94 energized for a period of time after the scale hopper is empty and in this way the scale mechanism and the conduit are blown free of flour. At the left of relay |02 is a scale discharge control relay |04 which exerts supervisory control over the discharging of flour from the scale hopper. This relay is in turn controlled by a scale control relay |06. Under some circumstances it is desirable to delay the discharging of our from the scale hopper for an extended period of time ,after the weighing operation has been completed. This operation is obtained by a scale discharge holding relay '|08 which is energized at the time the scale hopper has received the selected quantity of flour. The energization of this relay operates the scale printing mechanism H6 which records the weight of each quantity or batch of flour weighed out; relay |08 remains energized until it is desirable to convey the batch of our to a collector at which time this relay is de-energized.

With the present system each collector has a collector selecting switch positioned at its control station and when a batch of iiour is being delivered to one collector, the other collector selecting switches are rendered inoperative. In this way no harm results from the inadvertent closing of a second collector selector switch while the conveying operation is in progress. This function of the system is performed by a collector protective relay ||2 which is energized when each weighing operation is started and which remains energized during normal operation until the batch of flour has been weighed out and delivered to the selected collector.

Referring now to Figure 4e, at the dough-mixing station represented by collector 6| is a coilector selecting switch H4 which controls a collector setting relay ||6. Adjacent this relay is a valve protecting relay H8 and at the right is the main collector relay |20 which controls the valve operating mechanism |22 for valve 68. A pair of discharge control panels are represented at |24 and |26 at each of which are control switches and indicating lights; and at the right is a discharge control relay |28 which controls the double-vane discharge valve mechanism |30 for discharging iiour from the hopper at the bottom of the collector. The stations Afor collectors 65 and 66 have these same elements which are designated correspondingly by the suix 5 and 6, except that there is no valve 68 at collector 66 and therefore there is no mechanism corresponding to valve operating mechanism |22.

Referring now to left-hand side of the figure where the control mechanism at the two control stations is represented, the two stations are provided with an identical set of elements with the elements for station #I having no suix and the corresponding elements for station #2 being designated with the corresponding numbers with the sufx -2. In the present discussion, the elements of station #I will be explained in detail with the understanding that the elements of staamate for the stations of the three collectors 6|, 62 and l 68. There is also a normally open On push button switch |32 and a normally closed Ofi push button switch |34. The control station is also provided with a remote control scale head |36 which includes mechanism for setting the scale for the desired weight and also for indicating the weight of the material in the hopper. Near the bottom of panel |3| are two ilourselecting push button switches |38 and |40. the former of which is closed to select clear flour and the latter of which is closed to select patent iiour. Adjacent switch |38 is an indicating light |38 which is lighted upon the closing of this switch to indicate that clear flour has been selected, and adjacent switch |40 is a similar indicating light |4| which indicates when patent flour has been selected.

Station #I also includes the following: a Stop switch |42 which is closed to stop the weighing operation if such is desirable while these operations are in progress; a scale discharge switch |44 which is closed to initiate the delivery of flour from the hopper to conduit 58 after the scale stop switch has been operated and it is desired to deliver the flour in the hopper to the collectors; a main weigh control switch |46 which is operated to start the feeding of our to the scale hopper thus to carry out the weighing operation; a reset switch |52 which is closed to clear the circuits in the event that the operator desires to change a previously made selection of a collector thus to deliver a particular batch of flour to a collector other than one previously selected; and, an auxiliary weigh switch |48 which is closed to restart the weighing operation after it has been stopped for one reason or another, such, for example, by the closing of switch |42. Switch |48 has in series with it a normally-closed manual switch |50 which may be opened to render switch |48 inoperative.

As indicated above, station #l is provided with a normally open On push button switch 32 and a normally closed Off push button switch |34. These switches control a relay |56 which has a solenoid |54 and four armatures |58, |60, |62 and |64. This relay is held energized Whenever the system is being operated from station #l to carry on a weighing and conveying operation for one of its collectors 6|. 62 and 63. Station #2 is provided with a similar relay |56--2 which is energized whenever the system is being operated from station #2 and which has elements corresponding to those of relay |56 and designated with the sufx 2. These two relays are inter-connected so that when both of the relays are de-energized the closing of either one of the On switches (|32 or |32-2) completes a circuit to energize the associated relay; except that when either one of the relays is already energized, the closing of the On switch for the other relay has no eiect. Each of the On switches is connested at one side to the negative side of the power source and at the other side to its solenoid |54 or |54- 2). The other side of solenoid |54 is connected through line |66 to a contact |'61-2 which is engaged by armature |60-2 of relay |56-2 when this relay is de-energized. The energizing circuit for solenoid |54-2 is similar and includes a line |66-2 connecting the solenoid to a contact |61 which is engaged by armature |60 when relay |56 is de-energized. Armatures |88 and lill-2 are connected to the positive side of the power source and therefore when both sta' tions are idle, the closing of either of the On switches energizes the corresponding relay and this lifts the associated armature so as to open the circuit to the solenoid ofthe other relay.

Solenoid |54 has 'in parallel with it a pair of indicating lights |58 and |68-2 which are positioned respectively on panels |3| and |3|2 to be lighted when relay |56 is energized; thus to indicate that station #l is in use. Similarly, solenoid |54-2 has in parallel with it a pair of indicating lights |10 and |10-2 which are positioned respectively on the two panels and are lighted to indicate when station #2 is in use. Thus, at each station there is an indication as to which, if either, of the stations are being used.

Armature |58 is connected to the negative side of the power source and when in the raised position it engages a contact which is connected vthrough a line |12 to the Oil push button switch |34, the other side of which is connected to solenoid |54. Therefore, when switch |32 is closed momentarily so that armature |58 is raised by the energization of the relay, a lock-in circuit is completed to solenoid |54 through armature |58, line |12 and switch |34, and this circuit holds the solenoid energized even vthough. switch |32 reopens. Then, the relay may be readily de-energized by pushing push button switch |34 so as to open the switch and break the lock-in circuit. With this arrangement an operator at either of the stations ma)7 push his On" push button switch |32 and thus energize his relay and hold the system for his exclusive use.v When each weighing and conveying cycle has been completed armatures |58 and |58-2 are momentarily de-energized (by lmeans not shown) so that the relays are both de-energized; therefore, the weighing and conveying system is again available at either of the control stations.

Scale hopper 48 has associated with it three switches |14, |16 and |18 which are represented in Figure 4b, immediately above panels |3| and ISI-2 but which, in practice, are positioned at the scale hopper. Switch |18 remains closed when the scale hopper is in the zero weight position and it opens when the first quantity of material enters the hopper; as will be more fully explained below, this switch exerts control upon the system, for example, to prevent the inadvertent mixing of two different kinds of our in the scale hopper. During the weighing operation, flour is delivered to the scale hopper at a rapid rate until the amount of flour in the hopper approaches the desired quantity, whereupon the rate of delivery of iiour is reduced. Accordingly,

switch |14 is closed at the time the scale hopperA approaches the balanced condition and, as will be explained below, this reduces the rate of feed so that the scale hopper approaches its condition of balance at a very slow rate. When the exact quantity of iiour has been delivered to the scale hopper, the cut-off switch |16 is closed and this stops the feeding operation.

Assume that the system is not in use and that the operator at control Station #l wishes to weigh out and convey to collector 6| a batch of patent ilour from hopper 40. As is explained more fully below, this is possible only when the hopper of collector 6| has been emptied and its hopper discharge valve is open. Normally, the first step is to push the On push button switch |32 so as to energize relay |56, but the operator also checks the setting of the scale as' indicated the scale control relay |06.

on the scale control head |88 to make sure that the desired weight of our will be weighed out.

Armature |64 of relay |58 is connected to the' e. line |82 which is connected to one side of auxiliary weigh switch |48, stop switch |42, scale discharge switch |44 and reset switch |52 so that these switches are rendered effective. When the scale is at zero weight armature |62 of relay l56 is connected through a line |84 and switch E18 to the positive line and, therefore, the lifting of armature H62 connects the positive side of the battery through switch |18, line 84 and armature |62 to a contact |86 which is connected through a line E88 to one side of weigh switch i46 and the two rieur-selecting switches R38 and 40. thus to render all of these switches also eective.

The operator then selects patent our by closing push button switch i40, and this closes a circuit from the positive side of the power source to switch |40, as outlined above, and thence through a line i90 to the solenoid 92 of the patent our selecting relay 94; the other side of solenoid |92 is connected to the negative line so that this relay is then energized. This raises the armatures H94, |96 and i98 of this relay, and the armatures are held in the raised position by an automatic latch mechanism 260 which has a latch-releasing solenoid 202. When armature i198 of relay 84 is in its raised position, it connects the positive line through a line 204to signal lights i4| on the control panels i3d to indicate that patent flour selecting circuits have been set up.

As explained above, line i84 is connectedto the positive line through the zero scale switch |18. In addition to the connections referred to above, this line extends to the contact of armature i94 of relay 84; and therefore, When'thls armature is raised, the positive line is connected through armature 94 and line 206 to one side of each of the solenoids of bin protecting relay 88 and clear flour control relay 92. The other side 4of each of these solenoids is connected to the negativeline so that the setting up oi.' the circuit referred to above energizes these relays. Relay 88 has its armature 208 connected through a line 210 to armature |96 of relay 84 and, therefore, the raising of armature |96 connects armature 206 through a line 2l2 to e. contact 2|4 of This is a portion of the our feed control circuit to be referred to below. Armature 208 is raised by the energize.- tion of relay 88 so as to connect this circuit through a line 2|6 to armature 2|8 of relay 92 and, with relay 92 energized, the flour feed control circuit is extended through a line 220 to one side of each of solenoids 222, 254 and 224 of the flour feeding mechanism 82 of the patent flour bin 40. Solenoid 224 is the solenoid of a. two-position valve control relay 225 which has an armature 226 connected to the positive line.

When armature 226 is in the position shown,

it is connected through a line 221 to a valve-- closing solenoid 229 of a valve control mechanism 232. This mechanism has a valve-opening solenoid 230, a valve operating motor 234 and a limit switch 236 which has two armatures 238 and 239. Motor 234 is operated lto open and close the valve at the bottom of bin 40 and as the valve swings from and to the closed position these armatures are swung from and to the posil2 tion shown. Thus, the armatures are. in the right-hand position shown when the valve is closed with the result that armature 238 completes a circuit from the negative line to one side of solenoid 230. The other side of this solenoid is connected through line 228 to the upper contact of relay l225 and, therefore. with the valve closed the raising of armature 226 energizes solenoid 230 and thus completes a circuit to operate motor 234 in the proper direction to open the valve. The movement of the valve to the fully open position swings armatures 238 and 239 to the left so that the circuit through solenoid 28o is broken, but armature 23e-'moves into engagement with a left-hand contact so as to connect the negative line to solenoid 229. At this time,

" -however, armature 226 of relay 225 is latched in its raised position by a latching. mechanism which has a releasing solenoid 23 i, but when this solenoid is energized as outlined below armature 226 drops so as to connect the positive line s through line 221 to solenoid 229. This operates the relay so as to start motor 232 in such a direction as to close the hopper valve and when the valve is completely closed, armatures 238 and 239 swing back to the position shown so as to break the circuit to solenoid 229 and stop motor 234. v When armature 238 is in its left-hand position (that is, when the valve is open) it connects the negative line through a line 282, a scale overload switch 244 and a line 2136 to solenoid 222 and a solenoid 249. 'When solenoid 222 is energized it raises armature 248 which is connected to the negative line and thereby completes a circuit through a line 250 to a vibrator unit 252 which is connected to the positive line and is positioned on the side of the hopper at the bottom of bin all. Line 296 is also connected to solenoid 259 of the high-speed feed relay 255, the energizetion of which operates the high-speed feed motor 256 so as to feed lflour from bin i0 into the scale hopper at high speed. The other side of solenoid 254 is connected to line 220 so that when the bin valve is opened so as to energize line 296, and the flour feed control circuit including line 220 is also energized, our is fed by the operation of the high-speed feed motor 256. Line 246 is also connected to one side of the solenoid 249 of a low-speed feed relay 251, the energization of which completes circuits to operate a lowspeed feed motor 259. The other side of solenoid 249 is connected through a line 26| to the lower contact of armature 2|8 of relay 92.

Therefore, as will be explained below, the feeding operation from bin 40 is initiated by connecting the positive line through the flour feed control circuit outined above to line 220, and this initially energizes solenoid 224 of relay 225 so as to open the valve at the bottom of bin 40. When this valve is completely open armature 238 swings to the left with the result that the negative line is connected to solenoids 222, 254 and 249. At this time line 220 is still connected 4to the positive line so that the movement of armature 238 to the left energizes solenoids 222 and 254. The energizing of solenoid 222 starts the operation of the vibrator unit 252 and the energization of solenoid 254 starts the highspeed flour feed motor 256. As explained above, as the amount of our in the hopper approaches final weight, the rate of feed of flour to the hopper is reduced. This reduction is brought about by dropping armature 2|8 of relay 92 so as to deenergize line 220 and energize line 26|.

atrasos Thus, the high-speed ilour feed relay 255 is deenergized and the high-speed motor is stopped and the low-speed flour feed relay 251 is energized and the low-speed feed is started. At this time solenoid 222 is deenergized so as to stop the vibrator unit. The low-speed feeding operation continues until full weight is reached.

The selection of clear our by the operator is made by closing push button |38 and this initiates the delivery of clear our from bin 42 by energizing the clear flour feeding mechanism 88. The structure and operation of mechanism 88 is similar to that of mechanism 82 and the corresponding parts have been given corresponding numbers with the suiiix 2. Likewise, relays 86 and 98 operate in a manner. similar to relays 84 and 82 and the corresponding parts of relays 86 and 98 have also been identied by the suffix -2.

Either before or after the selection of the type of ilour, the operator also selects the collector to which the batch of flour is to be delivered. Therefore, assume that the operator closes collector selecting switch ||4 so as to select collector 8|. Switch I4 is connected at the left through a line 258 and armature 268 of the collector protector switch H2 to the positive line and the closing of switch ||4 completes a circuit to one side of solenoid 262 of the collector setting relay. The other side of this solenoid is connected through a line 264 and an armature 266 of valve protecting relay ||8 to the negative line; and, therefore, the closlng of the collector selecting switch energizes relay ||6 and the armatures are latched in their raised position by a latch assembly 268 having a latchreleasing solenoid 218.

Relay I I 6 has three armatures 212, 214 and 216. Armature 212 forms with its lower contact a switch 211 and at each of the collector stations there is a similar switch. These switches are connected in series by lines 288 288-5 between a line 218 and a line 282. Line 218 is connected to the latch-releasing solenoid 312 of collectorl protective relay H2, and also to one switch unit of each of the reset switches 252, the functions of which will be explained below; and line 282 is connected to the latch-releasing solenoid 283 of air feed relay 94 and also to the contact of the switch 285 of blowout relay |82 for purposes to be discussed below.

As discussed above, each of the collectors has a hopper into which the various quantities of flour are deposited and in which they may be temporarily stored. At the bottom of each hopper is a valve 1| which is normally open, but which is closed during the delivery of the flour to that hopper, and which remains closed until the operator discharges the flour. 'I'he valve is opened to discharge the flour and it remains open until that particular collector is selected to receive another quantity of iiour. The position of each Valve 1| is used to indicate whether or not its particular collector contains flour. For example, referring to Figure 1, the positions of the various valves 1| indicate that collectors 62 to 64 have received flour which has not been discharged from their respective hoppers; whereas, collectors 6i, 65 and 66 have been discharged after having last received flour.

The conditioning of a collector station to receive flour therefore involves rst the closing of its hopper valve 1i and this is done ina manner discussed more fully below at the time relay ||6 is rst energized. The closing of valve 1| swings the armatures of switch 295 to the right-hand position with the result that armature 294 connects line 282 to the positive line. Line 2824is connected to solenoid 298 o1' relay |28, and when amature 214 of relay ||6 is in its raised position, it engages a contact 286 which is connected through a line 288 to solenoid 298 which is thereby energized to set up the circuits for the valve operating mechanism for the valve 68 at collector 6|. The energization of solenoid 298 of relay |28 raises armatures 288, 29| and 293 and they are held raised by a latch 291 which has a latch-releasing solenoid 289. When all of the collectors have been out of use, so that all of collector relays |28 are deenergized, line 284 is connected to the negative line through a series circuit formed by a switch 296 of relay |28- 6 of collector 66, and a line 388 and a switch 382 of the valve operating mechanism |22 for each of the collectors 6| to 65. However, the valve operating mechanism for each of the valves 68 operates in the same manner as does the valve operating,r mechanism 232 described above and each of switches 382 is opened when its associated valve is opened to divert iiour into its collector. 'Iherefore, solenoid 298 of relay |28 is energized only when the discharge valve at the bottom of the collector is closed and all of valves 68 are closed, and the valve 68 at collector 6| can only be opened by the energization of relay |28 ybecause this relay controls the valve operating mechanism.

This valve operating mechanism is the same as the mechanism 232, described above, which operates the valve at the bottom of bin 48, and includes a valve operating motor 384 which operates the valve and simultaneously swings the armatures of a limit switch 38| between the right-hand position shown, wherein the lefthand armature 383 sets up a circuit to energize a valve-opening solenoid 385 when armature 393 is raised, and a left-hand position, wherein the right-hand armature sets up a circuit to energize a valve-closing solenoid 381 when armature 393 is in its lower position. As armature 383 swings to the left at the time the valve is opened, it connects the positive line through a line 389 to solenoid 3H of the valve-protecting relay H8. The other side of solenoid 3H is connected to the negative line so that relay I8 is energized whenever valve 68 for collector 6| is opened to divert flour into this collector.

Armature 216 of relay ||6 is connected to line 282 and when in the raised position it engages a contact connecting it through a line 386 to the contact of an armature 388 of the valve protecting relay H8. Armature 388 is connected through a line 3| 8 to the solenoid 3 i2 of the collector protective relay I2, the other side of which is. connected to the negative line. Line 282 is connected to the contact of switch 285 of the blowout relay, the armature of which, is connected to the positive line; and, at this time, the solenoid 3|5 of the blowout relay is energized due to being connected to the positive line through line 393 and armature 3|1 of the scale discharge relay |84. Therefore, line 282 is connected to the positive line, and the raising of armature 216 completes a circuit through a line 385, armature 388 and line 3|8 to energize solenoid 3I2 of the collector protective switch H2. This raises the armatures of this relay so that line 258 is disconnected from the positive line and, therefore, switches ||4 are rendered ineffective.

As pointed out above, the raising of armature 214 sets up the circuit for energizing solenoid 298 of relay |28 so that its armatures 289, 29| and 288 are raised. Armature 29| of relay |20 is connected to the positive line and the 'raising of this armature connects the positive line to a loading indicating light 3|9 on control panel |24 which is for the purpose of indicating to the operator that the circuits are then set for loading the collector. The other side of this loading indicating light is connected through line 32| to armature 266 of relay H8 through its upper contact with the armature being connected to the negative line; this armature is then being held in the raised position. The raising of armature 266 deenergizes solenoid 262' of relay H6, but the armatures of relay |I6 are held raised by the latch 268.

With the scale set for the desired weight and with the circuit set up so that the system is prepared to deliver patent ilour to the scale hopper and from the scale hopper to collector 6|, the weigh switch |46 is closed. This connects the positive line through the zero scale switch |18, line |84, armature |62, contact |68, line |88 and the weigh switch |45 to a weighing line 330. Line 330 is connected to an armature 332 of collector protective relay I |2 and with this relay energized, a circuit is set up through this armature and line 334 to one side of solenoid 336 of scale control relay |06. The other side of this solenoid is connected to the negative line so that the solenoid is thereby energized with the result that its armatures 338, 340 and v342 are raised. When armature 340 is raised, it engages contact 2 I4 so as to connect the flour feed control circuit referred to above through a line 344 to a contact which is engaged by an armature 346 of relay 86. Armature 346 is connected to the positive line so that the ilour feed control circuit is completed through the following: armature 346, line 344, armature 340, contact 2|4, line 2|2, armature |96, line 210, armature 208, line 2|6, armature 2|8 and line 220 to solenoids 222, 224 and 254. As outlined above, this initiates the feeding operation and our is fed to the scale hopper at a rapid rate.

When the initial quantity of flour flows into the hopper, switch |18 opens with the result that line |84 is disconnected from the positive line. This opens the circuit from the positive line to the solenoids of relays 92 and 88 with the result that the armatures of these relays will drop at any time that their armature latches are released. When the scale hopper approaches the nal weight position for which the scale is set, switch |14 closes and this connects the positive line through a line 348 to the latch-releasing solenoid 350 of the patent flour control relay 92. Therefore, the armatures of this relay fall so as to disconnect the flour control feed circuit from line 220 and to connect it to line 26|. As pointed out above, this stops the high speed feed motor 256 and starts the low speed feed motor 259. When the nal weight is reached, switch |16 closes thereby connecting the positive line 352 to the solenoid 353 of the scale discharge holding relay |08. Solenoid 353 is connected at its other side to the negative line so that the solenoid is energized and armatures 356, 358 and 360 are moved through a cycle. Armatures 356 and 358 and the contact of armature 360 are connected to the positive line, and armature 360 is connected through a line 362 to the latch-releasing solenoid 354 of the scale control relay |06.

It will be noted that solenoid 336 of scale control relay |06 is normally energized only momentarily by the closing of weigh switch |46 16 and, therefore, at this time the armatures of relay |06 are held in the raised position by the latch. Latch-releasing solenoid 354 of this relay is connected at one side to the negative line and, therefore, the raising of armature 360 of relay |08 energizes solenoid 354, thereby releasing the latch and permitting the armatures of relay |66 to drop. This opens the above-outlined flour feed control circuit because armature 346 moves away from contact '2|4 with the result that solenoid 248 is deenergized and the feeding operation is stopped immediately.

Line 362 is also connected to the latch-releasing solenoid 23| of relay 225 and the other side of this solenoid is connected to the negative line. Therefore, the raising of armature 360 also releases the latch of relay 225 and permits armature 226 to drop; and, the bin valve then being open and armature 238 being in the left-hand position, the valve-closing solenoid 229 of the valve operating mechanism. 232 is energized. This operates motor 234 to close the Valve. In this way the weighing operation is completed in a minimum length of time and immediately upon the scale reaching the desired ilnal weight the feeding operation is stopped. If for any reason the feeding operation should not be stopped at the proper time, the scale will not be overloaded because the scale overload switch 221i will open at such time as the scale has received a predeter= mined maximum amount of flour. This breaks thecircuit to solenoids 222, 256, and 268 so as to stop all feeding operations until the overload condition has been relieved. The lifting of armature 358 of the scale discharge holding relay connects the positive line to the scale printing mechanism |||l so as to print automatically the weight and the type of flour which has been weighed out.

If during the weighing operation the operator wishes to stop the feeding of flour to the scale hopper, he closes his stop switch |62 and this connects the positive line from armature |66, through line |82, vstop switch |42 and a line 366 to latch-'releasing solenoid 354 of the scale control relay |06, and also to latch-releasing solenoid 23| of relay 225. This stops the feeding operation in the same manner as does the raising of armature 36B of relay |08. The operator may then restart the feeding of flour to the scale hopper by closing his auxiliary weigh switch |48. This completes a circuit from line |82 through switch |48 to line 330 which is the line energized initially for starting the weighing operation. Therefore, if the system is in condition to make the weighing out of flour desirable, the weighing operation is restarted and carried to conclusion in the same manner as if it had never been stopped. Under some circumstances it is desirable to prevent the restarting of the weighing operation after it has once been stopped and. therefore, switch |50 is opened so that the auxiliary weigh switch is rendered ineiective.

It has been pointed out above that the normal operation is to select the type of ilour, the weight and the destination of the batch of our prior to starting the Weighing operation. However, if the operator wishes to change this selection once it has been made, he pushes his collector reset push button switch |52 thereby closing the switch units 365 and 361. These switch units are connected at one side to line |82 which, as pointed out above, is connected to the positive line through the switch |80. Therefore. the closing of switch unit 365 connects the positive line caracas l through a line 368. armature 342A of the scale control relay |06 and a line 388 to armatures 288 of the collector relays |20. Whenever a col-- lector has been selected, its relay |20 is energized so that the armature 288 of the selected collector engages its contact. These contacts are connected through lines 310 to their respective latchreleasing relays 210 o1' the collector setting relays ||6. Therefore, the closing of switch unit 365,; releases any collector setting relay which is then energized so that the operator can make a new selection of the collector to which the batch of ilour is to be delivered. The closing of switch unit 361 when line |82 is energized connects the positive line through this switch unit and line 218 to the latch-releasing solenoid 312 of collector protective relay ||2; the other side of solenoid 312 is connected to the negative line so that this closing of the reset switch 361 releases the armatures of the collector protective relay. Therefore, after a collector has been selected, the operator may cancel the selection and clear the circuits and he may then select another collector.

As pointed out above, the closing of the scale hopper switch |16 when the tlnal weight has been reached causes the scale discharge holding relay |08 to be energized; they cycle for this relay which is then carried on is as follows: Armature 360 is raised immediately, and, after three seconds, armature 358 is raised and is held raised for two seconds after which it is dropped, and, at that time armature 356 is raised. The raising of armature 360 connects the positive line to line 362, so that the feeding operation is stopped as explained above, and also so as to energize the latch-releasing solenoid 354 of relay |06 and drop the armatures 333, 340 and 342 of this relay. The dropping of armature 340 from its contact 2|4 opens the feed circuit (outlined above), and the dropping of armature 342 sets up the reset circuit (discussed above) from the reset switch unit 365 through line 366, armature 342 and line 368 to the various collector release armatures 288.

The raising of-armature 358 of relay |08 completes a circuit from the positive line to the scale printing mechanism H so as to print the final weight of the quantity of flour in the scale hopper. In addition to the weight, a record is made oi the type of iiour weighed out. For this purpose, lines 20d and 205, which extend 59 indicating lights iti and i 39 on panels l3| and EIM-2, are connected to relays (not shown) in the printing mechanism. Thus, at the time that the respective indicating lights 39 or |4| are lighted to indicate the type of flour selected, the corresponding relay in the printing mechanism is tripped so as to print an indication of the type oi' ilour then being weighed out. Thus, for example, when the patent our is selected and weighed out, the printing mechanism is conditioned to print-l an indication that a particular quantity of patent hour' was weighed out, and the raising of armature 358 causes the printing operation to be completed.

lt has been pointed out that immediately upon the energization of relay |08, the latch-releasing solenoid 354 of relay |06 is energized so as to release the armatures of this relay, and then five seconds later, armature 356 is raised. The raising of armature 356 connects the positive line through this armature and a line 314 to armature 338 which in turn is connected through a line 316 to the latch releasing solenoid 318 of the scale discharge control relay |04. Solenoid 380 of relay |04 is connected at one side to the negative line and at the other side to line |84 so that this relay is energized and its armatures 3|1 and 382 are lifted when each weighing cycle is started because the zero scale switch |18 is then closed. However, at the end o! the weighing operation, which is the portion of the cycle that we are now discussing, switch |18 is open and solenoid 380 o I relay |04 is deenergized. Thus, the raising of armature 356, and the resulting energization oi' solenoid 318 causes armatures 3| 1 and 382 of relay |04 to drop.

The dropping of armature 3|1 connects the positive line through this armature and a line 315 to the solenoid 311 of the air feed relay 84 so as to raise armatures 319 and 38| of this relay. The raising of armature 318 connects the positive line through a line 383 to the solenoid 38501' the valve motor relayv86 so as to raise its armatures 346 and 381. The raising or armature 346 disconnects line 344 from the positive line so as to open the feed circuit outlined above. The raising of armature 381 operates the motor control mechanism so as to start motor 81 which rotates valve 52 and delivers ilour from the bottom of the scale hopper into the stream of air in the aerator 56. The raising of armature 38| o! the air feed relay 84 connects the positive line .through a line 389 to the solenoid 38| of the hopper discharge relay 38 so as to open the hopper discharge valve 54 and so as to start the hopper vibrator |88. Thus, the flour is delivered from the scale hopper to the air stream in conduit 58 at a controlled rate and the ilour is carried by the stream of air to collector 6|.

The dropping of armature 382 of relay i04 connects the positive line to line 368, the energization of which, as pointed out above, releases any collector setting relay which is then energized. It was assumed above that the quantity of flour being weighed out was to be delivered to collector 6| and, therefore, it is now assumed that this collector is conditioned for use and the armatures of its relay H6 are raised. rfhus, the dropping of armature 382 completes a circuit from the positive line through line 368, armature 288 and line 310 to the latch-releasing solenoid 210, with the result that the armatures of relay H6 are dropped. However, the collector remains in condition to receive ilour and the dropping of these armatures merely conditions the circuits for later, operations which are discussed below.

When relay 20 is energized, as outlined above, the raising of armature 293 results in the energization of the valve-opening solenoid 305 so that the vane of the valve 68 for collector 6| is swung to divert our to the collector, and switch unit 302 is opened. The raising of armature 29| of relay |20 energizes the Loading signal light 3|8, and disconnects the positive line from a line 384 which is connected to one side of each of two push button control switches 386 positioned respectively on the control panels |24 and |26 and the adjacent Full signal lights 390. The other side of signal light 3|8 is connected through a line 32| to the upper contact of armature 266 of relay H8 which is at that time being held in raised position by the relay latch mechanism. Therefore, signal light 3|9 is lighted and it indicates to the operator at the control station that collector 6| is receiving flour.

When all of the nour has been discharged from the scale hopper, the scale returns to its zero weight position so that switches |14 and |16 are reopened and so that switch |18 is reatrasos 19 closed and line |84 is again connected to the positive line. This reenergizes solenoid 380 of relay |04 with the result that armatures 3H and 382 are lifted. The lifting of armature 882 opens the collector release circuit of line 368, etc. and this conditions this circuit for subsequent operations. The lifting of armature 3|1 deenergizes air feed relay 94 but its armatures are held in raised position by the latch mechanism, and, there-fore, the feeding operation continues. However, the raising of armature 3|1 of relay |08 also connects the positive line through a line 393 to solenoid 3|5 of the blowout relay |02. Blowout relay |02 has delayed action so that its switch unit remains open for fifteen seconds after its solenoid is energized and at that time the switch unit 285 closes and this connects line 282 to the positive line so as to energize solenoid 883 of the air feed relay 94 thus to drop armatures 319 and 38| and stop the feed motor 91 and vibrator and reclose valve 54.

Therefore, when the scale hopper is emptied and reaches the zero weight, relay |04 is ener- `glzed immediately but the feeding operation from the bottom of the scale hopper is continued for fifteen seconds to insure that all of the flour is delivered to the air stream in conduit 58, and, also to insure that all of this flour is delivered to the collector at the dough-mixing station. After this fifteen seconds delay, armatures 319 and 38| drop so as to deenergize relay 98 thereby stopping vibrator |00 and reclosing valve 54, and, also deenergizing relay 96. The deenergizing of relay 96 stops motor 9i and also connects the positive line through armature 346 to line 344 thus to condition this circuit for the starting of another feeding operation.

As pointed out abovel the deenergizing of relay |04 releases the armatures of the collector setting relay IIB so that the circuits are in their out-of-use condition. Thus, armature 214 drops away from its contact so as to deenergize solenoid 290 of relay |20, and armature 216 drops away from its upper contact so as to break the circuit to solenoid 3|2 of relay H2. However, both of relays |20 and ||2 have their armatures held in raised position by latch mechanism and, therefore, these armatures do not drop until the latches are released. The dropping of armature 212 of relay ||6 closes switch unit 211 and completes a circuit between lines 218 and 280 and the dropping of armature 216 completes a circuit from line 282 through a line 399 to the latch-releasing solenoid 299 of relay |20. As pointed out above, when all of the switch units 211 are closed, line 280 is connected to line 282, which, in turn, is connected to switch unit 285 of blowout relay |02. Therefore, at the time all of the hour has been delivered to the scale hopper and the blowout relay armature is lifted, a circuit is completed from the positive line through switch unit 285, line 282, armature 218 and line 399 to latch-releasing solenoid 299, so that the armatures 289, 29| and 293 of relay |20 are released. A circuit is also completed through switch unit 285, line 282, switch units 211 and lines 280 and 218 to latch releasing solenoid 312 of the collector protective relay ||2 so as to release armatures 280, 332 and 428. Thereleasing of armature 289 opens the collector releasing circuit, and the releasing of armature 293 energizes the valve closing solenoid 301 so as to close valve 88, and also so as to reclose switch unit 302. As pointed out above, switches 302,- line 300 and switch 295 of relay |20- 8 connect the negative 2@ line to line 284 so that during the conveying of flour to one of the colectors, the closing of one of the other collector relays H3 will have no' harmful effect. That is, with line 284 disconnected from the negative line, the collector selecting relay solenoids 290 cannot be energized.

'I'he releasing of armature 29| disconnects the positive line from the "Loading light Sie and connects the positive line through line 384 to the "Full lights 398 so that the operator is informed that the conveying operation has been completed. Line 384 is also connected to the flour discharge switches 888, the other side of each of which is connected through a line 394 to one side of solenoid 398 of the collector discharge relay |28, and

the other side of this solenoid. is connected to line 32 i. Therefore, when the operator wishes to discharge the flour from the collector hopper, he closes one of the push button switches 388 so as to energize solenoid 398 of relay |28 and rais'e armature 398 into engagement with its upper contact. This energizes the valve-opening solenoid 408 so as to operate motor |02 and open the hopper valve 'li at the-bottom of the collector. After this valve is completely open, the armatures of switch 285 are swung to the left thereby breaking the valve-opening circuit and stopping motor 402. This also sets up a valve-closing circuit for the valve-closing solenoid 404 from the positive line through armature 298 and its left-hand contact and a line 4|8 to the lower contact of armature 398, all in a manner explained above in connection with the discussion of -the valve operating mechanism 232.

The swinging of armature 293 of switch 295 to the left also opens the circuit of solenoid 290 so that relay |20 can not be energized again until the hopper valve 1| is reclosed. As pointed out above, the inlet valve 88 is moved to divert flour to collector 0l by the lifting of armature 293; thus, by preventing the energization of solenoid 290 so that armature 293 cannot be lifted when the outlet valve 1| is open, the flour-laden stream of air cannot be directed into the collector except when its hopper valve 1| is closed.

As pointed out above, when there is flour in the collector hopper, the armatures of relay ||8 are held raised and this prevents the selection of this collector to receive another quantity of our. However, when relay |28 is energized to discharge ilour (as outlined above), the raising of armature 406 connects the positive line through this armature and a line 408 to the latch-releasing solenoid 4|0 of relay |I8 sothat the armatures of this relay are permitted to drop. This deenergizes line 32| so that the Full signal lights 390 are extinguished and switches 388 are rendered ineective, although armatures 398 and 408 of relay |28 are held raised by the relay latch mechanism until the latch-releasing solenoid 4|2 is energized. Thus, the valve 1| for this collector is held open after the our has been discharged from the hopper until this collector is selected to receive another quantity of flour.

When this collector is to be used again, the closing of the collector selecting switch H4 completes a circuit through a line M4, armature 323 of relay ||8 which has been released and a line 4|8 to energize the latch-releasing solenoid 4|2 of relay |28. This drops armature 398 so that solenoid 4|0 is deenergized, and, also drops armature 408 so that/the valve closing solenoid 404 is energized through a line 4|8 with the result that the hopper valve is closed. The closing of this valve permits the valve 08 to be opened so as to divert 'arrancay 2 the flour-laden stream of air into the collector as outlined above.

As pointed out above, the delivery of flour to the scale hopper in any weighing and conveying operation is stopped automatically when the amount of flour in the scale hopper reaches the desired quantity. It was assumed above that a predetermined quantity of patent flour was t be delivered to collector 6|, but let us now assume that the desired quantity of flour is being weighed out and that part of it is in the scale hopper when the operator nds that he wishes to stop the operation and, therefore, he closes the stop switch |42. As explained above. this stops the feeding operation immediately and the operator has before him on the scale head |36, an indication of the amount of flour in the scale hopper. Let us also assume that the operator then determines, in accordance with the operation schedule, that he wishes to deliver this quantity of this particular flour to a certain collector. He then pushes the appropriate collector selecting switch I |4, and thereafter pushes the scale discharge push button switch |44 which has two switch units 420 and 422 which are in parallel. The closing of switch unit 420 completes a circuit from line |82 through a line 424 and an armature 426 of relay ||2 to line 352, and, with line |82 energized, this energizes the scale discharge holding relay |08 Withlout it being necessary to close switch |16. Similarly, the closing o switch unit 422 connects line l82 to line 348 so as to energize the latch-releasing solenoids of relays 82 and 80 without it being necessary to close switch |14. Therefore, the closing of switch |44 conditions the system and the weighed quantity of flour is delivered -to the selected collector in the same manner as if the' weighing operation had proceeded automatically to its normal conclusion. A

As pointed out above, the operator may stop the weighing operation by pushing the stop switch E42 and then he may wish to add an additional quantity of iionr to the scale hopper by pushing the auxiliary weigh switch |48. The closing of this switch completes a circuit from armature i84 through line |82 to line 330 and the feeding operation is carried on in the same manner as when the weighing operation is initiated by pressing the weigh switch |46.

In the above discussion it has been pointed out 'that relay 84 is energized by the depressing of one of the patent flour selecting push buttons |40 and the armatures of this relay are held in contact engaging position by a latch mechanism 200. When the weighing and-conveying operation is completed and the collector protective relay i|2 is released, the dropping of armature 260 connects the positive line to line 258. Line 258 is connected, as outlined above, to the collector selecting push button H4, but, it is also connected to the lower contacts of the upper armatures 430 and 430-2 of relays 92 and 80. Armature 430-2 is connected through line 432 to latch-releasing solenoid 282 of relay 84, and armature 430 is similarly connected through a line 432-2 to solenoid 202-2 of relay 86. Therefore, the dropping of armature 280 of relay ||2 energizes either one or bothY oi the latch releasing solenoids 202 or 202-2, depending upon whether one or both of armatures 430 or 430-2 are released.

The upper contacts of armatures 330 and 330-2 are connected directly to the positive line so that when either of these armatures is raised, the corresponding latch-releasing solenoid 202 or 202-2 -is energized and its armatures are released. In

22 this way, both of relays 84 and 88 are in released condition at the end of each weighing and conveying operation, and the energization of relay 92 releases relay 86, while the energization of relay releases relay 84.

Relay 88 has its armature lifted for the selection of patent our and its armature is held raised by a latch mechanism having a latch-releasing solenoid 436. clear our energizes solenoids 86 and 80 so that line |84, which is then connected to the positive line, is connected through armature |84-2 and a line 438 to solenoid 436 and to the energizing solenoid of relay 80. Therefore, if there has been a previous selection of patent our, the subsequent selection of clear ilour energizes solenoid 438 and releases armature 2084 so that the flour feed circuit, as outlined above, is connected through a line 2|6-2 to relay 90, and thence, to the clear flour feeding mechanism.

In the embodiment of Figure 5 the arrangement is similar to that of Figure 1 except that the various pneumatic conveyor systems are closed in the sense that the air is recirculated. 'Very little air is discharged from the systems, and minimum fresh air is drawn in. The various units in Figure 5 are numbered corresponding to those of Figure 1 except where there are diii'erences of structure. Thus, fan 28 discharges through blast gate 24 into conduit 8 rather than to atmosphere and with the blast gate at the outlet of the ian, the pressure in the system is accurately controlled. Fresh air is drawn in through lter 80|, and a vent pipe 800, having a damper thereon, is provided to discharge air if the pressure becomes excessive.

rIhe top of collector 44 discharges through a conduit 804 to the inlet of ian -36, with there being a damper 803 to control the pressure and a vent pipe 802 to relieve excess pressure. Fresh air is drawn in through lter unit 35. In a similar manner, conduit 6l is connected through a conduit 808 to the inlet of ian 60 and a vent pipe 808, having a damper thereon, is provided.

The arrangement of Figure 5 is particularly adapted for use where circumstances make the introduction of fresh air undesirable. Furthermore, this system may be used when the product being conveyed is subjected to a treatment during the conveying operation and the treating medium is in the form of a gas; such gases may be introduced in liquid form or from containers replacing the filter units.

ln the embodiment of Figure 6, the three pneumatic circuits are connected in series and at the left an air conditioning unit BIG is provided to impart to the air the desired temperature and humidity conditions. The air from unit 8|0 passes to conduit 8 and the air from fan 28 passes through a conduit 8|2 to fan 3B. The air from collector 44 passes through a conduit 8|4 to fan 80, and conduit 5l is connected through a conduit 8I6 to the air-conditioning unit 8|0. The system has a vent pipe 8|8, with a damper thereon. As pointed out above, air-conditioning unit 8|0 is provided with heating and cooling coils and humidifying means so that the air passing to conduit 8 will be so conditioned that the desired conditioning is imparted to the flour. This type of conditioning unit may be used elsewhere in the system of Figure 5 or in the other systems when desirable.

In the embodiment of Figures 1 and 4a, iour is conveyed from hopper 2 to collector l0 by a suction system, whereas, in Figure 7, a similar However, the selection 'oilA 23 system uses pressure at this point in the system. Thus, fan 28 draws in fresh air through a filter 820 and delivers air under pressure controlled by blast gate 24 to conduit 8, and collector I0 discharges directly to atmosphere. With this system it may be desirable to replace aerator 8 with a Venturi type of ilour pick-up arrangement. With this arrangement the cross-section of the air stream is reduced at the zone where our'is delivered to the air stream with the result that there is an increase in the rate of air-How and a decrease in the pressure. Thus, there is no tendency for air to be discharged upwardly through valve 4. This Venturi arrangement may -be adopted in all of the embodiments when desirable.

The various pneumatic conveyor systems herein disclosed include arrangements 'for adjusting the various blast gates to maintain the desired air velocity, either manually or automatically. Normally, the loading of an air stream tends to cause a substantial reduction in the air velocity and, therefore, the blast gates are opened to increase the pressure and maintain somewhat constant air velocity.

In the embodiments of the invention herein disclosed, a single sifter is provided for sifting the ilour before it is delivered to the storage and weighing station. Under some circumstances, it may be desirable to provide sifters at the doughmixing stations, either in place of or in addition to, the sifter here shown. It should also be pointed out that it may be desirable to omit the storage bins and to' provide only i'or temporary storage or for receiving iiour from the bags or containers in which it is transported. While the present invention has been disclosed in connection with a iiour conveying system, it is important to note that many of the important features are useful in connection with handling other materials.

As many possible embodiments may be made of the mechanical features of the above invention and as the art herein vdescribed might be varied in various parts, all without departing from the scope of the invention, it is to be understood that all matter hereinabove set forth, or shown in the accompanying drawings, is to be interpreted as illustrative and not in a. limiting sense.

I claim:

1. In a system for handling bulk products. the combination of, receiving means to receive the incoming product, a plurality of product-receiving units positioned respectively at remote stations, a pneumatic conveying system to carry the product from said receiving means to any one of said remote stations and including a' plurality of conduits and means to pass streams of air having the product entrained therein through said conduits and a plurality of product-separating units there being a unit operative to separate the product from the air flowing from each conduit forming a path for the product entrained in a stream of air, sifter means at a sifting station to sift the product after it is received by said receiving means and prior to delivery to any of said product-receiving units, and weighing means including scale hopper means positioned to receive the product after it passes through said sifting means and prior to delivery to any of said product-receiving units.

2. A system as described in claim 1 which includes, automatic control means to control the operation of the system.

3. A system as described in claim 2 which includes, means to control the weighing operation so that predetermined quantities of a selected product may be delivered selectively to the various remote stations, and means to prevent the changing a previous selection of a remote station after the delivery of a particular quantity of the product has been started.

4. A systemas described in claim 3 wherein said pneumatic conveying system for the product includes, a metering valve and an aerator, and wherein there is a single scale hopper and a single conduit extends from the scale hopper past said remote stations ln series, and valve means at the remote stations to direct the stream of air with the product entrained therein to theselected station.

5. A system as described in claim 3 wherein at least one of said means for separating the product from the air is a collector having primary and secondary stages which are of the cyclone separator type. f

6. A system as described in claim 5 wherein each of said pneumatic means and its means for separating the product from the air comprises structures forming passageways and coniining the flow so as to maintain a rapid air iiow throughout, thereby to prevent the depositing of the product except at the product outlets. 7. A system as described in claim 6 wherein the pneumatic means which receives the product from the receiving means is a suction system and comprises means forming a passageway and a suction device to draw air through said passageway, and a blast gate to control the suction pressure.

8. A system as described in claim '1 which includes, an electrical control system including a plurality of interlocking relays for controlling automatically the weighing of predetermined quantities of the product and the conveying of the quantities to the selected remote stations and means to control said electrical control system adjacent said remote stations.

9.`A system as described in claim 8 wherein one of said pneumatic means includes, a fan which draws air into the system through a iilter and which exhausts air from the system to atmosphere.

10. A system as described in claim 9, which includes sealing means at each of the outlets for the product from one of said primary and secondary stages whereby each of said stages is 'sealed during the collecting operation.

1l. In a. system for measuring and conveying selected quantities of bulk products from any one of a number of product storage bins to any one of a number of remote stations, the combination of, means to select the particular quantity of a product to be measured out and conveyed, means to measure out said particular quantity and to carry the product along a path which extends adjacent the various remote stations, means to select a particular station to which the selected quantity is to be delivered and to divert the product moving along said path to said particular station, relay means which is operated by the measuring out of the first of each quantity of the product thereby to prevent the selecting of another product until a pre-determined cycle of operations has been completed, and means to indicate to the operator the condition of the system and the progress of the measuring and conveying operations.

12. A system as described in claim 11 which includes, relay means to prevent the selecting of 

